


Student's Pet

by Crims0nKitty



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Alpha/Beta/Omega Dynamics, Alternate Universe - Modern Setting, Gift Exchange, Love Confessions, M/M, Smut, TKSSecretSanta2020, TKSevents, Teacher Xeno, Teacher-Student Relationship, TheKingomofShipping, Underage Senku, dubcon, implied established relationship, mild bondage, sub!Xeno lets gooooooooooo
Language: English
Status: Completed
Published: 2020-12-04
Updated: 2020-12-04
Packaged: 2021-03-10 03:33:27
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 4,536
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27867682
Author URL: https://archiveofourown.org/users/Crims0nKitty/pseuds/Crims0nKitty
Summary: It's hard being infatuated with your student...Especially when said student is the biggest 15 year old Alpha brat on the planet.But two could play at that game.
Relationships: Ishigami Senkuu/Dr. Xeno
Comments: 1
Kudos: 38
Collections: 2020 TKS Secret Santa





	Student's Pet

**Author's Note:**

> This is a TKS Secret Santa gift! 
> 
> I really hope you enjoy it!
> 
> \- Ivy~

The bustling halls of the school after the final bell told of the busy day the student’s and staff had before them. Student’s swarmed to their respective club rooms, many excited to help prepare for the club recruitment event taking place soon. Every club was looking forward to having new first year members, and the science club was just as excited as the rest.

Well, the club sponsor was, at least. The members of the club left the arrangement of the event up to him, many deciding to take the day off. Dr. Xeno carefully arranged the ingredients for his little science presentation he had planned. Everything had to be in the correct place: Petri dishes front and center with minimal distance between them, a spray bottle of ethanol on the right, long metal tongs on the left next to the flammable material he planned to burn for the students. His favorite being the 10,000 yen bill soaked in acetone: it was always a treat to see the panic on their faces before the vapors dissipated, leaving the bill untouched. 

“You're really doing that flame reaction test again?” Xeno’s hands froze, his dark eyes rising and a reserved smile crossing his face at the sight of the student in the stark white labcoat, his arms crossed over his chest.

“Ah, thank you for taking the time to join me,  _ Dr. Senku,” _ Xeno’s smile grew slightly once the tease reached the young Alpha’s ears. As snarky as the boy was, even he could be swayed by the occasional compliment.

Or perhaps it was because the compliment came from him?

Senku huffed, rolling his eyes as he entered the room and shut the door behind him with a brief click. The voices of passing students in the hallway became muffled and drained out by the barrier. It gave the illusion of privacy, though the school's science lab was hardly a place for those seeking such luxuries. “You did the same presentation at the last orientation, Doc.”

“I recall,” Xeno felt inside the cabinet under the counter, checking that the fire extinguisher was in the correct location. “It certainly caught your attention. Now you're the shining President of the Science Club, thanks to my elegant demonstration.”

Senku’s eyebrow shot up. “Caught my attention? You wish! I would’ve joined the Science club with or without your fancy flames.”

A soft chuckle left Xeno’s lips. “That may be true.” He admitted. In each of the petri dishes, he put a different chemical substance, raising his gaze across the counter to see Senku leaning over the surface, his inquisitive eyes never losing their shine as he watched the doctor’s steady hands. 

“I do the flame test every year for a simple reason. Children- ah, sorry, I know you hate to be called that.” Xeno grinned at the scowl across Senku's face; his soft, young features making the expression positively adorable.  _ “Young adults _ , much like yourself, tend to stray from STEM fields. The best way to get them interested is to get them excited, don’t you agree, Dr. Senku?”

A smirk appeared on the alpha’s lips. “And what’s more exciting to a bunch of high schooler’s than controlling fire… All right, I’ll give you that one. _ As long _ as you tell them the practical use behind the test as well.”

“Always the pragmatist. Very well.” Xeno stepped back from the experiment, smiling at his handiwork. He turned towards the desk at the front of the room to prepare to leave before raising an eyebrow at Senku. “Ah, my apologies, what can I assist you with? Did you have an experiment that you wanted to show to the students?”

“Nah.” Senku crossed his arms behind his head, walking around the table to meet Xeno at the other side. He stared directly into the teacher’s dark orbs with a wide grin. “I came to see you.”

“Is that so?” Xeno crossed his arms, eyebrow raised in amusement as he lifted his hand to tap a gloved finger against his chin. “What is it you need me for?”

“What, a guy can’t hang out with his favorite teacher?” 

Xeno saw the glint in Senku’s eye. How intriguing, it was rare for the young scientist to seek him out, his mind usually too engrossed in his latest projects to worry about his advisor. 

Xeno shrugged his shoulders, his lips curled with the smallest hint of humor. “I guess that is not uncommon for a teacher’s pet.”

“A  _ what?” _ Senku's eyes narrowed. “ _ I’m _ not the pet here.” 

The teacher did not expect Senku’s fingers to curl under one of the collars on his neck and pull him down to his level, seeing that wide smirk right in front of his wide eyes. 

“Why else would you wear these collars, huh?”

The alpha's scent was so strong. Spearmint and cedarwood with notes of ozone, overwhelming and perfect and so  _ him. _ The scent alone was enough to knock the teacher out of his cool, collected persona, but it didn’t help that the alpha’s scent was mixed with the obvious hints of arousal, adding a hint of spice to the tip of Xeno's tongue. 

Xeno suppressed the shiver that threatened to rack his body, holding his breath as he lightly pushed Senku’s hand away. “I would have assumed that I wouldn’t have to spell it out for you.” The teacher cleared his throat as he straightened the collar on his neck.

Senku chuckled as he slipped his hands into his coat pocket. “To hide your second gender, right?”

“That is one reason.” Xeno repressed his chuckle at the pondering look on Senku’s face. The student's eyes shined with curiosity. Of course the young alpha was curious of his teacher, he couldn't fault him for that. Many people sought to hide their second gender, but it was not the only reason. “What would be another?”

Senku thought for a moment, a hand slipping out of his pocket to hold onto his chin. The way his brows furrowed in thought was adorable, and his pause in thinking gave Xeno the chance to take a deep breath. 

Usually when someone presents as an Alpha, they tend to go one of two ways. Either they puff up and show off like a proud bird of paradise, or they do everything in their power to not look like one of intimidation... Senku did neither. The young scientist accepted the path that biology chose for him and moved on, determined to not let it change what he stood for.

Which would be admirable, if not for his strong scent. Most pubescent alphas and omegas used scent suppressants in their deodorant to counteract the strength of their strong hormones, but it seemed as though Senku did not get the memo. He ironically wore his heart on his sleeve for all to see. 

And his scent was irresistible. 

“My hypothesis…” Senku muttered, lifting his eyes to stare at Xeno’s collars. “If you truly are indeed an omega… Is to protect yourself from being marked.”

The teacher raised an intrigued eyebrow. “You seem hesitant to suggest that.” 

“With the laws and social norms set in place today, it is rare for anyone to be marked without distinct consent in place. Usually those who chose to wear protective collars were…”

A soft sigh left Xeno, the unspoken words reaching him loud and clear. He leaned against the counter, a reserved smile on his lips. “Your assumption is correct.”

“Sorry.”

“It’s not a bother.” Xeno responded softly with a sultry undertone. 

Senku smirked. “No, I mean, sorry for grabbing you like that.”

A soft laugh burst through Xeno’s lips. “Your apologies are not needed. I can assure you that I can handle a bit of  _ rough treatment.” _

Xeno saw the way Senku tensed before the scent of his arousal met him. Ah, to be a hormonal teenager again, always bouncing back when things got suggestive. But there was some reluctance in Senku’s stance, the confidence lacking in his deep gaze. 

Now, it wouldn't be any fun if Senku were reluctant, now would it? 

“I was about your age when I was attacked," Xeno admitted, waving his hand in the air. "Nearly marked, as was my attacker’s intention, when a close friend of mine saved me. He gave me the collars: one to mask my scent, another to completely hide my neck.” 

Xeno’s hand traced the old leather, his mind replaying the night Stanley gave him the collars. It was his first heat after the attack, where he was scared of his own urges and the tears wouldn’t stop streaming down his face. Stanley made him feel safe, helped him retake the power that he had lost... made sure that Xeno would not be held back by his own trauma. 

“I’ve decided for myself that I will never be marked. I will belong to no one. These collars are a symbol of that decision.”

“Damn,” Senku blinked. A moment later his grin returned. “And here I thought you were just edgy.”

Xeno huffed, his lips curling at the return of his student’s snappy mouth. “The style of my collars are completely my choice, thank you.” He ran his hand across it, like one tightening their tie. “I find them to be quite fetching.”

“Sure, if you’re style is a dog.”

“You should watch your mouth.”

“Or what, you gonna shove something in it?”

Xeno smirked, taking a step forward to erase the space between them. “I just might…” He raised Senku’s chin with his thumb and forefinger and stared into his deep red orbs. “Perhaps my pet needs a muzzle…”

_ Click. _

Xeno could only blink. Upon looking down, he saw a long black leash hanging from the top collar on his neck. His brows furrowed, looking up to see the self satisfied grin on Senku’s face. “What is the meaning of this?”

_ “Heel.” _

Xeno gasped as the sharp tug from the leash brought him to his knees. Xeno grasped at the leather, looking up in disbelief.

Senku chuckled darkly. “Who’s the pet now?”

“S-stop this childish-” Another yank. Another gasp. Xeno’s cheeks flushed as he grasped at the fabric of Senku’s pants.

“Heh, you look good on your knees, Dr. Xeno,” Senku smirked. “But we already knew that, didn’t we?” Senku’s fingers gently stroked through Xeno’s silver locks before gripping the back of his head by the roots, forcing him to look directly up. “Will you be a good boy for me?”

Shallow pants left Xeno’s parted lips, his face flushed in humiliation. Senku’s stare was so dark and alluring, and when he strained his eyes to look down he could see the outline of something thick in Senku’s pants.

Xeno’s eyes squeezed shut, turning his head away. “Stop these games before someone comes in. Are you trying to get us caught?”

“Hey, we’re not doing anything wrong.” Senku took a step back, releasing Xeno’s hair to pull a chair out from under a counter. “Besides, what’s wrong with a fun little game?”

Xeno sighed, grip still tight on the leash as he watched Senku sit. “I guess  _ children _ do like games, don’t they?”

Senku scoffed. “You’re being a brat today.” 

Xeno chuckled, a sly remark about to leave his lips when Senku stuck his shoe in front of his face. 

“All of this could be over…” He waved his foot in front of his teacher’s nose “If you kiss my foot.”

Xeno’s jaw dropped. I mean the nerve of this child. “I would never!”

“Come on Doc, we all know you got a foot thing.”

_ “I certainly do not!” _

“Uh-huh, yeah, like you don’t want people to kiss your feet.”

“That’s-” Xeno felt the heat leave his face as he turned his head away from Senku. “It’s more about the power dynamic than the  _ feet!” _

Senku chuckled as he took off his shoe, slowly pulling off his sock and pointing his foot at the doctor. “ _ That’s  _ why I’m doing this. Kiss it.”

Xeno glared at the foot, lifting his glare to Senku’s haunting grin. The kid was so confident, so damn cocky...

Xeno grinned.

Senku yelped when Xeno pressed his nose against the bottom of his foot, lips brushing against the soft underside. Senku’s scent was stronger here, mixed with the stench of sweat and musk, coaxing a groan out of Xeno’s mouth, tongue slipping past his parted lips to tickle the sensitive area and get the tiniest taste of his skin.

Senku pulled his foot away, stumbling over his words, blushing all the way to his ears.

Xeno straightened his posture with a confident smirk. “You’re not very good at this game you're playing.”

“Fuck you.” Senku snapped. He pulled on the leash, forcing Xeno’s face into his lap. The scientist’s gasp was muffled by the student’s pants, and the musky smell that invaded Xeno’s nose nearly made him whimper. Senku gripped Xeno’s hair, forcing his head down as he rocked his bulge against Xeno’s face. “You’re such a fucking slut. I should have known you would do something like that. Fuck, I bet you’d let me do anything I wanted to you. Won’t you, Dr. Xeno?”

Xeno bit his lip to hold back the sounds in his throat. His cheek felt sore from the friction, but the heat and the smell was making his mind foggy.

Xeno gasped when Senku pulled his head back, crimson eyes boring into a dark abyss. “I asked you a question, Doc.”

A low whine escaped Xeno’s lips, eyebrows furrowed as he squeezed his eyes shut. “A-alpha…”

“Fuck…” Senku grabbed his advisor’s wrists, holding them together as he wrapped the leather leash around them. “Bend over. Now.” He ordered, his voice more deep and demanding than Xeno had ever heard before, and the omega obeyed him, turning around and leaning forward on his forearms, head low with his butt held high.

Senku flipped up the black lab coat, his hands immediately starting to explore the fabric of Xeno’s slacks, up his thighs and eventually caressing his round cheeks. Xeno’s heart beat with excitement when he heard a low, rumbling growl behind him, feeling Senku press his erection against him as he fumbled with Xeno’s belt and pants.

“What…?” Realization was dawning on Xeno when he heard the long zip from his zipper, breaking him out of his instincts to submit. “What do you think you’re doing?”

“Shut up.” Senku growled, fingers curling into the clothing and pulling them away from Xeno’s fair skin. “You want this. Fuck, your scent…” The student’s breath caught when Xeno became bare. Slick was dripping from his winking hole, and Senku grabbed the soft globes as he leaned forward, taking in a deep, shaking breath. Like black raspberries and vanilla. “That’s what you smell like…  _ Damn.” _ Senku’s shaky voice nearly came out as a moan.

“S-stop this- Ah!” Senku’s tongue came as a shock, lapping at his entrance with studious care, his student's moans sending out vibrations that made Xeno shudder, heat spreading from his face down to his shoulders. “I don’t want this!”

Senku tightened his grip on Xeno’s ass, grinning as he flattened his tongue and left a long lick from his perineum to the tight little hole. “I think you do, doc.”

Xeno shook his head, shuttering at the pleasure traveling through him. “Whatever gave you the impression?”

“Let’s see…” Senku began, the clear arousal seeping through his voice. “Giving me your phone number?” He bit at the soft skin of Xeno’s ass to make him jump. “Contacting me outside of school?” He flicked his tongue against his hole again.

“That was- Ah! P-Professional!” Xeno stumbled with his words. “Helping you with science projects…”

“Oh, and meeting me alone all the time?”

“You're…!” Xeno moaned when Senku’s tongue pushed inside of him, licking up his slick eagerly. Xeno's nails dug into the skin of his palm as he repressed his wanton moans. “You’re the president of the Science Club, meeting is perfectly normal…”

Senku hummed, pulling away and wiping his mouth on the back of his hand with a wide grin. “How about when you sucked my dick after I won first place at nationals?”

“Oh. That.” Xeno chuckled, smiling over his shoulder. “You can’t blame me for being curious. You presented as an alpha but you’re so…  _ small. _ I just had to see if you had the knot to match.”

Senku’s grip on his hips became unbearably tight. “Oh yeah? And what were your findings?”

Xeno laughed, his eyes dark with lust as his gaze lowered to Senku’s pants. “You’re anything but small, alpha.”

Senku growled, releasing one hand to fumble with the fastening of his pants. “That’s right… I remember your face when I popped my knot. You had to use both hands to stroke me, and you drank every ounce of my cum before walking away like you weren’t the biggest fucking slut in the world.”

Xeno’s eyes were wide when Senku’s hard dick was freed, standing proud and tall. It was absolutely beautiful, smooth and leaking precum. 

Senku was absolutely elegant.

And Xeno needed him to breed him right now-

Xeno bit his lip, suppressing his omega desires. “Please tell me you have a condom.” 

Senku grinned. “Yeah, bought it with your leash.”

The teacher’s head fell forward, hot pants leaving his mouth. He spread his knees a bit, lining himself up at an appropriate angle for Senku.

The alpha let out a long whistle. “Damn, you’re so hot, presenting yourself to me.”

He choked on a moan as the compliment went straight to Xeno’s dick. “Alpha, please…”

Two fingers slipping inside him made the doctor hiss. He wanted to scold Senku for skipping a step, but his body eagerly took his finger’s, even enjoying the rough treatment that Senku’s virgin fingers were giving. Perhaps Senku caught on to this, his pace soon picking up, scissoring and curling at seemingly random intervals. Though there was likely a method to Senku’s madness, Xeno was falling too deep to tell or care at this point. Long moans were leaving his lips, and he began to unconsciously rock back onto Senku’s fingers.

“Fuck, Xeno…”

The arousal in the room was getting overwhelming. Xeno could tell that Senku was holding back, trying to focus on not hurting Xeno instead of giving into his desires to take the omega as his own. It took effort, but Xeno reached up to his neck, unlatching the bottom collar before attempting to push himself up. 

“Senku…”

Senku’s hazy eyes looked up, blinking in surprise as Xeno slipped off the bottom collar. A moment later it hit him in: The strong smell of raspberry and the unmistakable scent of Xeno’s arousal.

“Alpha… Senku,  _ please.” _

Senku’s eyes turn dark as a growl ripped through his throat. He pushed his teacher back down, grabbed his hips and lined up his tip to his hole. 

He pushed in slowly, a strangled gasp leaving his mouth as he was surrounded by Xeno’s warmth. Xeno mewled at the stretch before biting on his knuckles to keep silent. 

Although that point was debatable - when the alpha was moaning loudly behind him as he bottomed out, Xeno felt pride. He made the alpha make those noises, he got to have Senku’s first time,  _ and _ he was going to make it good.

He clenched tightly on Senku, causing said alpha to tighten his grip on Xeno’s hip enough to leave delicious bruises the omega would treasure. The alpha pulled out a bit before slamming back in, his past fast and uneven in his inexperience as he chased his desire. Xeno couldn’t find it in himself to care, especially since even in Senku’s inexperience, the alpha knew enough about the human body to aim. Every uneven hit to Xeno’s prostate was like a random number generator of pleasure, leaving the teacher thrilled and on his edge to see where each new thrust would leave him, each level of intensity bringing out interesting noises from his mouth.

Senku suddenly leaned forward, wrapping his arms around Xeno’s waist, hips still moving at a stumbling pace. “So good…. Fuck, you’re so good, my omega. Only mine.  _ Mine.” _

Xeno’s lip quivered. “Yes, alpha...! Only yours! Fill me with your seed, please... I want-- Aha, I want to have your pups!”

A breathless chuckle left Senku’s mouth. “Fuck, I love it when you beg.” He whispered against his neck, grabbing the leash and tugging it back to pull Xeno up until he stood on his knees. Xeno barely had a chance to catch his breath before Senku kissed him. His eyes closed, head tilting to give Senku better access, feeling his student’s tongue exploring his mouth as if committing it to memory. Senku bit Xeno’s lip before pulling away, his hand traveling down Xeno’s stomach until he wrapped his hand around Xeno’s aching cock. “If you want my pups, you’re going to have to be a good boy and come for me. Can you do that?”

Xeno nodded, whimpering as Senku began his slow, torturous stroking. He rolled his hips, trying to get as much stimulation as possible. He wanted to come... he never wanted to come so bad in his life, not even during his heat. All he wanted was Senku’s cum filling him until his stomach filled and nothing else in life mattered -

The sound of laughter from the hallways brought both of them down from their highs. Students were passing the science lab, chatting happily with one another without a care in the world.

It was as if Senku had fucked his senses out of Xeno; he quickly came to the realization of just how terrible the consequences would be if he was caught with his student.

Xeno felt another wave of pleasure pass through him with this thought. But they needed to stop, this was unprofessional, after all!

He tried to move away, attempting to knock Senku’s hand away and stop this before they got caught, but Senku’s grip on the leash strengthened and his teeth caught on Xeno’s lab coat, holding the omega in place.

Senku’s hand sped up on Xeno’s cock, and Xeno bit his tongue until he tasted blood to prevent himself from crying out. A tremor rocked his body as he came, spilling his seed across the floor as he clenched on Senku’s dick. The alpha pushed the omega down, fucking into him fast and hard, his breathing stuttering as his knot formed, stretching the omega's walls to their limit. 

“Xeno, fuck...I’m coming!” He whispered against his neck as he pressed in as deep as he could go, covering his mouth to suppress his moan as he came inside of Xeno. Xeno shivered, his walls still clenching to milk Senku of every last drop of his seed, the sensation so great that Xeno came again. After 15 hot, pleasurable seconds, the teacher fell limp to the cold floor below as he tried to catch his composure.

The sounds of student’s faded away until the only thing the bonding pair could hear was their panting filling the lab room. Their scents blended together, with the smell of their love making and sweat mixed in as well. There was a mess on the floor of slick and cum, and Xeno’s clothes were uncharacteristically wrinkled, but neither of them could find it in themselves to care.

Senku’s hands traveled over the bare parts of his teacher’s body, sighing in content as he nuzzled against his back. Xeno chuckled at Senku’s uncharacteristic affection, but it was common for alphas to be more affectionate after an orgasm. Xeno hummed, pleased with the affection he received from his young alpha. “That was a delightful game.”

Senku chuckled. “Yeah, I just didn’t expect you to fight me so much.”

“Not every omega is submissive, you know.”

“Heh, I didn’t even know you were an omega. It would just be my luck to fall for a beta or another-”

Senku went silent, and Xeno raised an eyebrow as he looked over his shoulder. “Something the matter?”

“Nothing. Forget I said anything.”

Xeno stared for a moment, a smile slowly growing across his face. “Are you perhaps embarrassed to admit your attraction to me?”

“Shut up, like I would do something like that.” 

The teacher laughed. “I feel it’s a little late to be embarrassed while you’re knotting me.”

Senku huffed. “This is just sex.”

“Sex with your omega. Isn’t that lovely?”

Senku’s hold around Xeno tightened. “You’re not anyone’s omega. You’re your own person.”

Xeno’s smile turned soft. “Yes. But with you I feel different. Maybe one day I can be yours.”

Senku slowly raised his head, a grin across his face. “Don’t be such a sap.”

Xeno huffed, lowering his head. “I wont waste my breath, then.”

Senku chuckled, testing their little predicament with a little tug of his hips, causing Xeno to gasp. “Whoops, sorry. Not ready yet.”

“Give it ten more minutes, you should deflate enough by then.”

“Got it.” Senku rested his cheek on Xeno’s back. A light silence filled the room, leaving Xeno time to make a mental checklist of the descenters and cleaning they would need to do to hide the evidence of their lewd deeds, when Senku hummed behind him. “What does this mean? For us, I mean…” He asked quietly against his back.

Xeno sighed. “More hiding, more secret conversations in plain sight, probably more public sex;” He chuckled. “It means that my feelings aren’t going unrequited.”

“Pfft, duh.” Senku hugged Xeno tighter. “I said don’t be a sap… But of course I feel the same. How could I  _ not _ fall for the person who mentored me since I was 10?”

Xeno pursed his lips. “I have no idea what you’re talking about.”

“Shut up,  _ Dr. X. _ You text the exact same way. And your emails stopped after you became my advisor, dumbass.”

“Ah.” Xeno blinked. The lack of email exchanges slipped his mind as communication never stopped between him and Senku. 

Senku chuckled. “Shotacon.” 

Xeno huffed at his accusation. “You’re fifteen!”

“Still underage.”

“...You’re just loving this.”

“Ten billion points, doc.”

Xeno chuckled, shaking his head before resting it on his hands. “You're incorrigible.”

“Thanks.”

The teacher closed his eyes. “And I love you, too." He said right above a whisper. He felt Senku move slightly at his remark and it left a warm feeling in his chest.

“Turn around.” 

Xeno blinked, turning his head, his eyes widening when Senku pressed his lips against his. His eyes closed, melting into the kiss from the teen he had fallen for so long ago. 

When they parted, Senku smirked against his teacher’s lips. “We should meet up outside of school sometime. I’d especially love to help you during your heat.”

“If you can find a way to assure that no one would find out about us, then be my guest.” Xeno offered. “And perhaps next time you can leave me untied?”

“Nah. Think I’m gonna stick a gag in your mouth and slap you with a riding crop.”

_ “Oh…” _

Senku raised an eyebrow. “You like that?”

“Very.”

Senku chuckled, pressing his nose against Xeno’s scent gland, pressing a soft kiss against his mentor's neck. “Get excited, then.”

**Author's Note:**

> If you would like to leave a comment but not have it posted, please let me know!


End file.
